from The Open University
Alternatively you can skip the navigation by pressing 'Enter'.
The RavensSunday, 19th April 2015 04:05 - BBC World Service RadioA social work student brefriends a sex worker in Sydney - but how easy is changing a life? The second of two... Read more: The Ravens: 24th International Radio Playwriting Competition winner
Thinking Allowed: The Ethnography Award 'Shortlist' 2015Monday, 20th April 2015 00:15 - BBC Radio 4
Secret History Of... Deptford High StTuesday, 21st April 2015 20:00 - BBC Four
Secret History Of... Deptford High StWednesday, 22nd April 2015 02:00 - BBC Four
A History of Ideas - Descartes Cogito Ergo SumAvailable until Thursday, 14th April 2016 08:30Stephen Fry explains Rene Descartes argument 'Cogito Ergo Sum' - 'I think, therefore I am'. Watch now: OU on the BBC: A History of Ideas - Descartes Cogito Ergo Sum
A History of Ideas - Erving Goffman's Performed SelfAvailable until Thursday, 14th April 2016 08:15
Thinking Allowed: The Ethnography Award 'Shortlist' 2015Available until Friday, 15th April 2016 09:45
A History of Ideas - John Locke and personal memoryAvailable until Thursday, 14th April 2016 11:15
What does it mean to be me?Watch these short and snappy animations on the subject of me: the individual, memory, 'self' and... Watch now: What does it mean to be me?
Take the photographic memory testCan you capture scenes just by looking at them? Find out with our photographic memory test. Launch now: Take the photographic memory test
Introduction to bookkeeping and accountingThis free course Introduction to bookkeeping and accounting provides an introduction to the... Try: Introduction to bookkeeping and accounting now
Succeed with maths – Part 1[BETA] If you feel that maths is a mystery that you want to unravel then this short 8-week course... Try: Succeed with maths – Part 1 now
Energy resources: Solar energy
Energy from sources other than fossil and nuclear fuels is to a large extent free of...
Energy from sources other than fossil and nuclear fuels is to a large extent free of the concerns about environmental effects and renewability that characterize those two sources. Each alternative source supplies energy continuall, whether or not we use it, and most have their origins in energy generated outside the Earth, yet the potential of each is limited by its total supply set against its rate of use. The Sun will radiate energy until it ceases thermonuclear fusion, in around 5 billion years. This unit explores the Sun as a potential source of usable energy.
By the end of this unit you should be able to:
- explain the principles that underlie the ability of various natural phenomena to deliver solar energy;
- outline the technologies that are used to harness the power of solar energy;
- discuss the positive and negative aspects of solar energy in relation to natural and human aspects of the environment.
Energy resources: Solar energy
Energy from sources other than fossil or nuclear fuels is to a large extent free of the concerns about environmental effects and renewability that characterise those two sources. Each alternative source supplies energy continually, whether or not we use it. Many alternative sources of energy have been used in simple ways for millennia, e.g. wind and water mills, sails, wood burning – but only in the last two centuries has their potential begun to be exploited on an industrial scale. Except for geothermal energy, all have their origins in energy generated outside the Earth, yet the potential of each is limited by its total supply set against its rate of use. Each is likely to be renewable in the sense that the available rates of supply of each exceed those at which they are used. The main concern is whether or not such alternatives can supplant fossil- and nuclear-fuel use to power social needs fast enough to avoid the likelihood of future global warming and other kinds of pollution.
One of the alternative sources to consider is solar energy.
The Sun will radiate energy until it ceases thermonuclear fusion, in around 5 billing years. About 33% of the solar power that enters the Earth's system heats the atmosphere and contributes to setting winds and waves in motion. Of that reaching the Earth's surface, 70% falls on the sea, setting in motion ocean currents and a large proportion of the circulation of water vapour in the atmosphere because of evaporation from the ocean surface. The remainder falls on the land. Solar energy is redistributed through interlinked surface systems:
- the carbon cycle based on photosynthesis;
- atmospheric circulation and the water cycle;
- winds and ocean waves; and the ocean current system.
Each of them is a potential source of useable energy. In every case, with the exception of the energy available from surface water flow, humanity comes nowhere near exploiting the Sun's potential to supply useable energy; in fact, we really do not know the practical limits. Whatever those are, they will not disappear as a resource – all are renewable. Compare this with the solar energy stored chemically by the degraded products of photosynthesis in fossil fuels. Although carbon burial adds continually to that resource, its pace of renewal (between 1 to 10 GW – Figure 1) is about 2000 times slower than we use it. Fossil fuels are non-renewable and declining extremely quickly in terms of human history.
This unit explores Solar power as a source of directly useable energy.
This unit is from our archive and is an adapted extract from Earth's physical resources: origin, use and environmental impact (S278) which is no longer taught by The Open University. If you want to study formally with us, you may wish to explore other courses we offer in.
This is an extract from an Open University course which is no longer available to new students. If you found this interesting you could explore more free Environmental Science course units or view the range of currently available OU Environmental Science courses.